Communications device, infrastructure equipment and methods

ABSTRACT

A communications device for use in a wireless communications network providing a wireless access interface within a system bandwidth, the system bandwidth comprising a plurality of bandwidth parts, the communications device comprising a transmitter configured to transmit signals using a plurality of activated bandwidth parts, a receiver configured to receive signals using the plurality of activated bandwidth parts, the received signals being signals transmitted using a plurality of activated beams, and a controller configured to control the transmitter and the receiver so that the communications device is operable: to determine that an activated beam associated with a first bandwidth part satisfies beam failure criteria; to select from the plurality of activated bandwidth parts a second bandwidth part; and to transmit using communications resources associated with the selected second bandwidth part a beam failure indication indicating that the activated beam associated with the first bandwidth part satisfies the beam failure criteria.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.17/270,037, filed Feb. 22, 2021, which is based on PCT filingPCT/EP2019/073604, filed on Sep. 4, 2019, which claims priority to EP18195309.2, filed Sep. 18, 2018, the entire contents of each areincorporated herein by reference.

BACKGROUND Field

The present disclosure relates to communications devices, infrastructureequipment and methods for the communication by a communications devicewith an infrastructure equipment in a cell of a wireless communicationsnetwork.

Description of Related Art

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

Third and fourth generation mobile telecommunication systems, such asthose based on the 3GPP defined UMTS and Long Term Evolution (LTE)architecture, are able to support more sophisticated services thansimple voice and messaging services offered by previous generations ofmobile telecommunication systems. For example, with the improved radiointerface and enhanced data rates provided by LTE systems, a user isable to enjoy high data rate applications such as mobile video streamingand mobile video conferencing that would previously only have beenavailable via a fixed line data connection. The demand to deploy suchnetworks is therefore strong and the coverage area of these networks,i.e. geographic locations where access to the networks is possible, maybe expected to increase ever more rapidly.

Future wireless communications networks will be expected to supportcommunications routinely and efficiently with a wider range of devicesassociated with a wider range of data traffic profiles and types thancurrent systems are optimised to support. For example it is expectedfuture wireless communications networks will be expected to efficientlysupport communications with devices including reduced complexitydevices, machine type communication (MTC) devices, high resolution videodisplays, virtual reality headsets and so on. Some of these differenttypes of devices may be deployed in very large numbers, for example lowcomplexity devices for supporting the “The Internet of Things”, and maytypically be associated with the transmissions of relatively smallamounts of data with relatively high latency tolerance.

In view of this there is expected to be a desire for future wirelesscommunications networks, for example those which may be referred to as5G or new radio (NR) system/new radio access technology (RAT) systems[1], as well as future iterations/releases of existing systems, toefficiently support connectivity for a wide range of devices associatedwith different applications and different characteristic data trafficprofiles.

Another example of such a new service is referred to as Ultra ReliableLow Latency Communications (URLLC) services which, as its name suggests,requires that a data unit or packet be communicated with a highreliability and with a low communications delay. URLLC type servicestherefore represent a challenging example for both LTE typecommunications systems and 5G/NR communications systems.

The increasing use of different types of communications devicesassociated with different traffic profiles gives rise to new challengesfor efficiently handling communications in wireless telecommunicationssystems that need to be addressed.

SUMMARY

The present disclosure can help address or mitigate at least some of theissues discussed above.

Embodiments of the present technique can provide a communications devicefor use in a wireless communications network, the wirelesscommunications network comprising an infrastructure equipment providinga wireless access interface within a system bandwidth, the systembandwidth comprising a plurality of bandwidth parts, the communicationsdevice comprising a transmitter configured to transmit signals using aplurality of activated bandwidth parts, a receiver configured to receivesignals using the plurality of activated bandwidth parts, the receivedsignals being signals transmitted using a plurality of activated beams,and a controller configured to control the transmitter and the receiverso that the communications device is operable: to determine that anactivated beam associated with a first bandwidth part satisfies beamfailure criteria; to select from the plurality of activated bandwidthparts a second bandwidth part; and to transmit using communicationsresources associated with the selected second bandwidth part a beamfailure indication indicating that the activated beam associated withthe first bandwidth part satisfies the beam failure criteria.

Embodiments of the present technique, which further relate toinfrastructure equipment, methods of operating communications devicesand infrastructure equipment and circuitry for communications devicesand infrastructure equipment, allow for efficient use of resources formeasuring and reporting the status of beams used for the transmission ofsignals on communications resources associated with a plurality ofbandwidth parts.

Respective aspects and features of the present disclosure are defined inthe appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, but are notrestrictive, of the present technology. The described embodiments,together with further advantages, will be best understood by referenceto the following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings wherein likereference numerals designate identical or corresponding parts throughoutthe several views, and:

FIG. 1 schematically represents some aspects of a LTE-type wirelesstelecommunication system which may be configured to operate inaccordance with example embodiments of the present disclosure;

FIG. 2 schematically represents some example aspects of a new radioaccess technology (RAT) wireless communications network which may beconfigured to operate in accordance with embodiments of the presentdisclosure;

FIG. 3 illustrates a portion of a wireless access interface, in whichthe system bandwidth comprises multiple bandwidth parts which may beactivated and deactivated independently;

FIG. 4 schematically shows a telecommunications system according to anembodiment of the present disclosure;

FIG. 5A and FIG. 5B illustrate in plan view an example configuration ofa beams within a cell configured according to embodiments of the presenttechniques;

FIG. 6 illustrates a portion of a wireless access interface, in whichthe system bandwidth comprises multiple bandwidth parts which may beactivated and deactivated independently and in which one of thebandwidth parts is designated as a primary bandwidth part;

FIG. 7 illustrates a process flow chart for a communications device inaccordance with embodiments of the present technique; and

FIG. 8 illustrates a further process flow chart for a communicationsdevice in accordance with embodiments of the present technique.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Long Term Evolution Advanced Radio Access Technology (4G) FIG. 1provides a schematic diagram illustrating some basic functionality of amobile telecommunications network/system 100 operating generally inaccordance with LTE principles, but which may also support other radioaccess technologies, and which may be adapted to implement embodimentsof the disclosure as described herein. Various elements of FIG. 1 andcertain aspects of their respective modes of operation are well-knownand defined in the relevant standards administered by the 3GPP (RTM)body, and also described in many books on the subject, for example,Holma H. and Toskala A [2]. It will be appreciated that operationalaspects of the telecommunications networks discussed herein which arenot specifically described (for example in relation to specificcommunication protocols and physical channels for communicating betweendifferent elements) may be implemented in accordance with any knowntechniques, for example according to the relevant standards and knownproposed modifications and additions to the relevant standards.

The network 100 includes a plurality of base stations 101 connected to acore network part 102. Each base station provides a coverage area 103(e.g. a cell) within which data can be communicated to and fromcommunications devices 104, and within which a communications device mayobtain service. Data is transmitted from the base stations 101 to thecommunications devices 104 within their respective coverage areas 103via a radio downlink Data is transmitted from the communications devices104 to the base stations 101 via a radio uplink. The core network part102 routes data to and from the communications devices 104 via therespective base stations 101 and provides functions such asauthentication, mobility management, charging and so on. Communicationsdevices may also be referred to as mobile stations, user equipment (UE),user terminals, mobile radios, terminal devices, and so forth. Basestations, which are an example of network infrastructureequipment/network access nodes, may also be referred to as transceiverstations/nodeBs/e-nodeBs, g-nodeBs and so forth. In this regarddifferent terminology is often associated with different generations ofwireless telecommunications systems for elements providing broadlycomparable functionality. However, example embodiments of the disclosuremay be equally implemented in different generations of wirelesstelecommunications systems, and for simplicity certain terminology maybe used regardless of the underlying network architecture.

That is to say, the use of a specific term in relation to certainexample implementations is not intended to indicate theseimplementations are limited to a certain generation of network that maybe most associated with that particular terminology.

FIG. 2 is a schematic diagram illustrating a network architecture for anew RAT wireless communications network/system 300 based on previouslyproposed approaches which may also be adapted to provide functionalityin accordance with embodiments of the disclosure described herein. Thenew RAT network 300 represented in FIG. 2 comprises a firstcommunication cell 301 and a second communication cell 302. Eachcommunication cell 301, 302, comprises a controlling node (centralisedunit) 321, 322 in communication with a core network component 310 over arespective wired or wireless link 351, 352. The respective controllingnodes 321, 322 are also each in communication with a plurality ofdistributed units (radio access nodes/remote transmission and receptionpoints (TRPs)) 311, 312 in their respective cells. Again, thesecommunications may be over respective wired or wireless links. Thedistributed units 311, 312 are responsible for providing the radioaccess interface for communications devices connected to the network.Each distributed unit 311, 312 has a coverage area (radio accessfootprint) 341, 342 which together define the coverage of the respectivecommunication cells 301, 302.

Each distributed unit 311, 312 includes transceiver circuitry fortransmission and reception of wireless signals and processor circuitryconfigured to control the respective distributed units 311, 312.

In terms of broad top-level functionality, the core network component310 of the new RAT communications network represented in FIG. 2 may bebroadly considered to correspond with the core network 102 representedin FIG. 1 , and the respective controlling nodes 321, 322 and theirassociated distributed units/TRPs 311, 312 may be broadly considered toprovide functionality corresponding to the base stations 101 of FIG. 1 .The term network infrastructure equipment/access node may be used toencompass these elements and more conventional base station typeelements of wireless communications systems. Depending on theapplication at hand the responsibility for scheduling transmissionswhich are scheduled on the radio interface between the respectivedistributed units and the communications devices may lie with thecontrolling node/centralised unit and/or the distributed units/TRPs.

A communications device 400 is represented in FIG. 2 within the coveragearea of the first communication cell 301. This communications device 400may thus exchange signalling with the first controlling node 321 in thefirst communication cell via one of the distributed units 311 associatedwith the first communication cell 301. In some cases communications fora given communications device are routed through only one of thedistributed units, but it will be appreciated in some otherimplementations communications associated with a given communicationsdevice may be routed through more than one distributed unit, for examplein a soft handover scenario and other scenarios.

The particular distributed unit(s) through which a communications deviceis currently connected through to the associated controlling node may bereferred to as active distributed units for the communications device.Thus the active subset of distributed units for a communications devicemay comprise one or more than one distributed unit (TRP). Thecontrolling node 321 is responsible for determining which of thedistributed units 311 spanning the first communication cell 301 isresponsible for radio communications with the communications device 400at any given time (i.e. which of the distributed units are currentlyactive distributed units for the communications device). Typically thiswill be based on measurements of radio channel conditions between thecommunications device 400 and respective ones of the distributed units311. In this regard, it will be appreciated that the subset of thedistributed units in a cell which are currently active for acommunications device will depend, at least in part, on the location ofthe communications device within the cell (since this contributessignificantly to the radio channel conditions that exist between thecommunications device and respective ones of the distributed units).

In at least some implementations the involvement of the distributedunits in routing communications from the communications device to acontrolling node (controlling unit) is transparent to the communicationsdevice 400. That is to say, in some cases the communications device maynot be aware of which distributed unit is responsible for routingcommunications between the communications device 400 and the controllingnode 321 of the communication cell 301 in which the communicationsdevice is currently operating, or even if any distributed units 311 areconnected to the controlling node 26 and involved in the routing ofcommunications at all. In such cases, as far as the communicationsdevice is concerned, it simply transmits uplink data to the controllingnode 321 and receives downlink data from the controlling node 26 and thecommunications device has no awareness of the involvement of thedistributed units 311, though may be aware of radio configurationstransmitted by distributed units 311. However, in other embodiments, acommunications device may be aware of which distributed unit(s) areinvolved in its communications. Switching and scheduling of the one ormore distributed units may be done at the network controlling node basedon measurements by the distributed units of the communications deviceuplink signal or measurements taken by the communications device andreported to the controlling node via one or more distributed units.

In the example of FIG. 2 , two communication cells 301, 302 and onecommunications device 400 are shown for simplicity, but it will ofcourse be appreciated that in practice the system may comprise a largernumber of communication cells (each supported by a respectivecontrolling node and plurality of distributed units) serving a largernumber of communications devices.

It will further be appreciated that FIG. 2 represents merely one exampleof a proposed architecture for a new RAT communications system in whichapproaches in accordance with the principles described herein may beadopted, and the functionality disclosed herein may also be applied inrespect of wireless communications systems having differentarchitectures.

Thus example embodiments of the disclosure as discussed herein may beimplemented in wireless telecommunication systems/networks according tovarious different architectures, such as the example architectures shownin FIGS. 1 and 2 . It will thus be appreciated the specific wirelesscommunications architecture in any given implementation is not ofprimary significance to the principles described herein.

In this regard, example embodiments of the disclosure may be describedgenerally in the context of communications between networkinfrastructure equipment/access nodes and a communications device,wherein the specific nature of the network infrastructureequipment/access node and the communications device will depend on thenetwork infrastructure for the implementation at hand. For example, insome scenarios the network infrastructure equipment/access node maycomprise a base station, such as an LTE-type base station 101 as shownin FIG. 1 which is adapted to provide functionality in accordance withthe principles described herein, and in other examples the networkinfrastructure equipment/access node may comprise a controlunit/controlling node 321, 322 and/or a TRP 311, 312 of the kind shownin FIG. 2 which is adapted to provide functionality in accordance withthe principles described herein.

The embodiments of the present invention can find application withadvanced wireless communications systems such as those referred to as 5Gor New Radio (NR) Access Technology. Systems incorporating NR technologyare expected to support different services (or types of services), whichmay be characterised by different requirements for latency, data rateand/or reliability. For example, Enhanced Mobile Broadband (eMBB)services are characterised by high capacity with a requirement tosupport up to 20 Gb/s. The requirements for Ultra Reliable & Low LatencyCommunications (URLLC) [1] services are for a reliability of 1-10⁻⁵(99.999%) for one transmission of a 32 byte packet with a user planelatency of 1 ms [3]. Massive Machine Type Communications (mMTC) isanother example of a service which may be supported by NR-basedcommunications networks.

The elements of the wireless access network shown in FIG. 1 may beequally applied to a 5G new RAT configuration, except that a change interminology may be applied as mentioned above.

Bandwidth Part

A communications device and an infrastructure equipment, such as thecommunications device 104 and infrastructure equipment 101 of FIG. 1 ,are configured to communicate via a wireless access interface. Thewireless access interface may comprise one or more carriers, eachproviding, within a range of carrier frequencies, communicationsresources for transmitting and receiving signals according to aconfiguration of the wireless access interface. The one or more carriersmay be configured within a system bandwidth provided for the wirelesscommunications network of which the infrastructure equipment 101 formspart. Each of the carriers may be divided in a frequency division duplexscheme into an uplink portion and a downlink portion and may compriseone or more bandwidth parts (BWPs). A carrier may be configuredtherefore with a plurality of different BWP for a communications deviceto transmit or receive signals.

The nature of the wireless access interface may be different amongst thedifferent BWPs. For example, where the wireless access interface isbased on orthogonal frequency division multiplexing, different BWPs mayhave different sub-carrier spacing, symbol periods and/or cyclic prefixlengths. BWPs may have different bandwidths.

By configuring BWPs appropriately, the infrastructure equipment mayprovide BWPs which are suited for different types of services. Forexample, a BWP more suitable for eMBB may have a larger bandwidth inorder to support high data rates. A BWP suited for URLLC services mayuse a higher sub-carrier spacing and shorter slot durations, in order topermit lower latency transmissions.

Parameters of the wireless access interface which are applicable to aBWP may be referred to collectively as the numerology of a BWP. Examplesof such parameters are sub-carrier spacing, symbol and slot durationsand cyclic prefix length.

FIG. 3 shows an example of first to third BWPs 401 a-c configured withina system bandwidth 410 extending from frequency f1 to frequency f6. Thefollowing Table 1 provides a summary of the characteristics of each ofthe BWPs 401 a-c:

TABLE 1 Summary of BWP characteristics Index Frequency Sub-carrier BWP(bwp-id) range spacing 401a 1 f1-f4 15 kHz 401b 2 f2-f3 15 kHz 401c 3f5-f6 60 kHz

As shown in Table 1, each BWP may be identified by an index number(bwp-id).

In the example in FIG. 3 , the BWPs 401 a-c do not collectively span theentire system bandwidth 410. However, in some examples, the frequencyrange of one or more BWPs collectively span the system bandwidth 410 (inother words, all frequencies in the system bandwidth may fall within atleast one BWP). A frequency range of a BWP may be entirely within thefrequency range of another BWP (in this case, the second BWP 401 b iswithin the bandwidth of the first BWP 401 a).

A BWP may comprise communications resources for uplink or downlinkcommunications. For a communications device, an uplink (UL) BWP and adownlink (DL) BWP may be independently configured, and an association(e.g. pairing) of an UL BWP and a DL BWP may be configured. In someembodiments, uplink and downlink communications resources are separatedin time, in which case time division duplexing (TDD) may be used. Incase of TDD, a BWP-pair (UL BWP and DL BWP with the same bwp-id) mayhave the same centre frequency. In some embodiments uplink and downlinkcommunications resources are separated in frequency, in which casefrequency division duplexing (FDD) may be used. Where FDD is used, a ULBWP and a DL BWP may comprise two non-contiguous frequency ranges, onecomprising communications resources for uplink communications and onecomprising communications resources for downlink communications. In theremainder of the present disclosure, the term ‘bandwidth part’ (BWP) isused to refer to a pair of associated uplink and downlink bandwidthparts and as such, may comprise communications resources for both uplinkand downlink transmissions. The terms ‘uplink bandwidth part’ and‘downlink bandwidth part’ will be used where appropriate to refer to abandwidth part comprising only, respectively, uplink communicationsresources and downlink communications resources.

An activated BWP refers to a BWP which may be used for the transmissionor reception of data to or from the communications device 104. Aninfrastructure equipment may schedule transmissions to or by thecommunications device 104 only on a BWP if that BWP is currentlyactivated for the communications device 104.

On deactivated BWPs, the communications device 104 may not monitor aPDCCH and may not transmit on PUCCH, PRACH and UL-SCH.

Conventionally, as illustrated in FIG. 3 , at most one BWP providinguplink communications resources and at most one BWP providing downlinkcommunications resources may be activated at any given time in respectof a particular communications device. In the example of FIG. 3 ,initially (prior to time t1), only the first BWP 401 a is activated. Attime t1, the first BWP 401 a is deactivated and the second BWP 401 b isactivated. Subsequently, at time t2, the second BWP 401 b isdeactivated. From t2 to t3, only the third BWP 401 c is activated; fromt3 to t4 only the second BWP 401 b is activated, and at t4, the firstBWP 401 a is activated and the second BWP 401 b is deactivated.

In light of the differing numerologies which may be applicable to BWPs,a single activated BWP may not be suitable for the transmission of dataassociated with different services, if those different services havedifferent requirements (e.g. latency requirements) or characteristics(e.g. bandwidth/data rate). Additionally or alternatively, there may beinsufficient capacity on a single BWP for the requirements of a singlecommunications device. Therefore, consideration has been given to thepossibility of activating multiple BWPs for a single communicationsdevice.

Prior to being activated, a BWP may be configured for use by thecommunications device 104. That is, the communications device 104 maydetermine the characteristics of the BWP, for example, by means of radioresource control (RRC) signalling transmitted by the infrastructureequipment 101.

Beams

According to some radio access technologies, including the new radio(NR) radio access technologies under development by 3GPP, a cell may beformed (or, in other words, ‘generated’) by a plurality of directionalbeams. Each beam may be characterised by a variance in gain with respectto a direction from the antenna; a beam may be considered ‘wide’, wherethe gain is consistently relatively high over a broad range ofdirections, or ‘narrow’, where relatively high gain is only achievedover a narrow range of directions. Depending on the direction of thecommunications device with respect to the infrastructure equipment, thegain of a particular beam may be sufficiently high (and the resultingcoupling loss sufficiently low) to permit communications between thecommunications device and the infrastructure equipment via the beam.

Beams may be formed for transmitting or receiving at the infrastructureequipment using phased antenna arrays, directional antennas, acombination of both, or other known techniques.

Communications resources such as a particular BWP may be associated withone or more beams. In other words, the infrastructure equipment maytransmit or receive using communications resources on all, or somesubset of beams. A beam may be said to be ‘activated’ in respect ofcommunications resources, if the infrastructure equipment transmits orreceives on those communications resources using that beam. For example,one or more beams may be activated in respect of a BWP. Differentcommunications devices within the same cell may use different sets ofbeams.

However, there is a need to provide efficient means to monitor andmanage the usage of multiple beams in a scenario where multiple BWPshave been activated for a single communications device.

According to embodiments of the present disclosure, there is providedcommunications device for use in a wireless communications network, thewireless communications network comprising an infrastructure equipmentproviding a wireless access interface within a system bandwidth, thesystem bandwidth comprising a plurality of bandwidth parts, thecommunications device comprising a transmitter configured to transmitsignals using a plurality of activated bandwidth parts, a receiverconfigured to receive signals using the plurality of activated bandwidthparts, the received signals being signals transmitted by theinfrastructure equipment using a plurality of activated beams, and acontroller. The controller is configured to control the transmitter andthe receiver so that the communications device is operable: to select afirst bandwidth part from the plurality of activated bandwidth parts; todetermine that an activated beam associated with the selected firstbandwidth part satisfies beam failure criteria; to select from theplurality of activated bandwidth parts a second bandwidth part; totransmit to the infrastructure equipment using resources associated withthe selected second bandwidth part a beam failure indication indicatingthat the activated beam associated with the selected first bandwidthpart satisfies the beam failure criteria.

Initial, Primary and Default BWPs

A BWP may be designated as an initial BWP, which provides the controlresource set for downlink information used to schedule downlinktransmissions of system information.

A BWP may be designated as a primary BWP which is always activated andwhich may be used for transmitting control information to or by thecommunications device 104. Since the primary BWP is always activated andthus may be used for data transmission, it may only be necessary toactivate one or more further (secondary) BWPs if the primary BWP isunsuitable for an ongoing or new service or insufficient e.g. due tocongestion or lack of bandwidth.

Alternatively or additionally, a BWP may be designated as a default BWPIf no BWP is explicitly configured as a default BWP, a BWP which isdesignated as the initial BWP may be the default BWP.

A default BWP may be defined as a BWP that a UE falls back to after aninactivity timer, associated with a BWP other than the default BWP,expires. For example, where a non-default BWP is deactivated as a resultof an associated inactivity timer expiring, and no other non-default BWPis activated, then a default BWP may be activated in response.

A default BWP may have an activation or deactivation priority whichdiffers from the activation or deactivation priority of other,non-default, BWPs. A default BWP may be preferentially activated and/ormay be deactivated with lowest preference. For example, a default BWPmay remain activated unless and until a further BWP is to be activatedsuch that a maximum number of activated BWPs would be exceeded.

A default BWP may further be preferentially used for transmitting anindication that a different BWP is to be activated or de-activated.

FIG. 4 schematically shows a telecommunications system 500 according toan embodiment of the present disclosure. The telecommunications system500 in this example is based broadly around an LTE-type architecture. Assuch many aspects of the operation of the telecommunicationssystem/network 500 are known and understood and are not described herein detail in the interest of brevity. Operational aspects of thetelecommunications system 500 which are not specifically describedherein may be implemented in accordance with any known techniques, forexample according to the current LTE-standards.

The telecommunications system 500 comprises a core network part 102coupled to a radio network part. The radio network part comprises theinfrastructure equipment (which may be an evolved-node B) 104 coupled,via a wireless access interface illustrated generally by arrow 508, to acommunications device 104 (which may also be referred to as terminaldevices). It will of course be appreciated that in practice the radionetwork part may comprise a plurality of base stations serving a largernumber of communications devices across various communication cells.However, only a single infrastructure equipment and singlecommunications device are shown in FIG. 4 in the interests ofsimplicity.

As noted above, the operation of the various elements of thecommunications system 500 shown in FIG. 4 may be broadly conventionalapart from where modified to provide functionality in accordance withembodiments of the present disclosure as discussed herein.

The infrastructure equipment 101 is connected to the core network 102via an interface 510 to a controller 506. The infrastructure equipment101 includes a receiver 504 connected to an antenna 518 and atransmitter 502 connected to the antenna 518. The receiver 504 and thetransmitter 502 are both connected to the controller 506. The controller506 is configured to control the infrastructure equipment 101 and maycomprise processor circuitry which may in turn comprise varioussub-units/sub-circuits for providing functionality as explained furtherherein. These sub-units may be implemented as discrete hardware elementsor as appropriately configured functions of the processor circuitry.Thus the controller 506 may comprise circuitry which is suitablyconfigured/programmed to provide the desired functionality usingconventional programming/configuration techniques for equipment inwireless telecommunications systems. The transmitter 502, receiver 504and controller 506 are schematically shown in FIG. 4 as separateelements for ease of representation. However, it will be appreciatedthat the functionality of these elements can be provided in variousdifferent ways, for example using one or more suitably programmedprogrammable computer(s), or one or more suitably configuredapplication-specific integrated circuit(s)/circuitry/chip(s)/chipset(s).As will be appreciated the infrastructure equipment 101 will in generalcomprise various other elements associated with its operatingfunctionality.

Correspondingly, the communications device 104 includes a controller 516connected to a receiver 514 which receives signals from an antenna 520.The controller 516 is also connected to a transmitter 512 which is alsoconnected to the antenna 520. The controller 516 is configured tocontrol the communications device 104 and may comprise processorcircuitry which may in turn comprise various sub-units/sub-circuits forproviding functionality as explained further herein. These sub-units maybe implemented as discrete hardware elements or as appropriatelyconfigured functions of the processor circuitry. Thus the controller 516may comprise circuitry which is suitably configured/programmed toprovide the desired functionality using conventionalprogramming/configuration techniques for equipment in wirelesstelecommunications systems. The transmitter 512, receiver 514 andcontroller 516 are schematically shown in FIG. 4 as separate elementsfor ease of representation. However, it will be appreciated that thefunctionality of these elements can be provided in various differentways, for example using one or more suitably programmed programmablecomputer(s), or one or more suitably configured application-specificintegrated circuit(s)/circuitry/chip(s)/chipset(s). As will beappreciated the communications device 104 will in general comprisevarious other elements associated with its operating functionality, forexample a power source, user interface, and so forth, but these are notshown in FIG. 4 in the interests of simplicity.

Beam Management

FIGS. 5A and 5B show in plan view a use of multiple beams within thecell 103, their activation for BWPs, and a notification message sentfrom the communications device 104, which may be in accordance withembodiments of the present technique.

In the example shown in FIG. 5 , to form the cell 103, theinfrastructure equipment 101 forms a number of beams, of which only afirst beam 150, a second beam 152 and a third beam 154 are shown.

The infrastructure equipment 101 may configure the communications device104 by means of, for example, RRC configuration, with one or more beamsincluding the first to third beams 150, 152, 154. All or a subset ofthese configured beams may be activated for transmission of signalsrepresenting data to the communications device by the infrastructureequipment. The activated beams may be used for the transmission ofcontrol or data, including control messages including initial accessmessages, mobility management control messages, and user data fromhigher protocol levels (such as non access stratum user plane data).

Communications resources of a BWP may be associated with one or moreactivated beams. For example, as shown in the table of FIG. 5A, firstand second beams 150 and 152 may be associated with (or ‘activated’ inrespect of) the first BWP 401 a; similarly, the third beam 154 may beactivated for the third BWP 401 c.

Certain communications resources may be preconfigured for use fortransmissions on only a single beam. The communications device 104 maybe aware of the mapping of these communications resources to beam(s) bymeans of RRC configuration or other means. Communications resourceswhich are used for transmissions on a single beam may be used by theinfrastructure equipment to transmit reference signals orsynchronisation signals. Alternatively or additionally, transmissionsusing a beam may include an indication of an identity of the beam.

The communications device 104 may measure signals transmitted onconfigured beams, whether or not they are activated. These signals maycomprise channel state information reference signals (CSI-RS) orsynchronisation signal blocks (SSB) transmitted using predeterminedcommunications resources associated with a single beam. By measuringthese signals, the communications device 104 can determine whether aparticular beam meets predetermined beam failure criteria. Beam failurecriteria may be satisfied if, for example, a received signal strengthand/or a received signal quality fall below a predetermined beam failurethreshold. This may occur as a result of signal blockage or rotation ormovement of the communications device 104.

For example, in the example shown in FIG. 5A, the communications device104 is within the high gain region of the first to third beams 150, 152,154. As indicated by the ‘tick’ marks in the table, in the situationrepresented in FIG. 5A, none of the beams which are activated for one ofthe activated BWPs satisfy the beam failure criteria.

However, the communications device 104 may be moving, as indicated bythe arrow 156. After some time, the situation may be as shown in FIG.5B, in which the communications device 104, having moved relative to theinfrastructure equipment 101, is no longer within the high gain regionsof the second and third beams 152, 154. As a result, based onmeasurements are performed by the communications device 104 of receivedsignals which were transmitted on communications resources used only fortransmissions using the second and/or third beams 152, 154, or which areotherwise identifiable as being transmitted using those beams, thecommunications device 104 determines that the signal strength and/orsignal quality of those signals are below the respective predeterminedbeam failure threshold and that the beams have therefore satisfied thebeam failure criteria. To indicate this, the second and third beams 152,154 are shown in FIG. 5B with dashed, rather than solid, lines, and theticks of the table of FIG. 5A have been replaced by crosses to indicatethis.

In response to this determination, then in accordance with embodimentsof the present technique as will be described in further detail below,the communications device 104 may transmit a beam failure indication 160to the infrastructure equipment 101. The beam failure indication 160 inthe example of FIG. 5B may indicate that the second and third beams 152,154 have satisfied the beam failure criteria.

In response, the infrastructure equipment 101 may adapt the number andcharacteristics of the beams of a cell over time. Alternatively oradditionally, the infrastructure equipment 101 may de-activate oractivate one or more beams in respect of a particular BWP.

For example, the infrastructure equipment 101 may modify the set ofactivated beams, for example, by transmitting an indication (not shown)to the communications device 104 that a configured fourth beam (notshown) is now to be activated, and that the currently activated secondand third beams 152, 154 are to be deactivated.

Beam management as used herein refers collectively to processes andtechniques such as those described in the example above, and which mayinclude one or more of the measurement of signals transmitted on one ormore beams, an assessment as to whether one or more beams satisfyrespective beam failure criteria, indications (such as the beam failureindication 160) transmitted by the communications device 104 to theinfrastructure equipment using an activated BWP to indicate whether ornot one or more beams satisfy respective beam failure criteria, theconfiguration or activated set of beams are modified, and transmissionsindicating control information relating to the beams sent using anactivated beam which has not satisfied the beam failure criteria.

Beam Failure Recovery

As has been described above, provided at least one activated beamremains available for communication, then beam management processes canupdate and adapt the set of activated beams in response to one or morebeams becoming unsuitable.

However, should all activated beams satisfy the beam failure criteria,then it is necessary to initiate a procedure to recover from thissituation. This procedure is referred to as beam failure recovery. Sinceall activated beams satisfy the beam failure criteria, the beammanagement procedures described above are not appropriate.

In an example beam failure recovery procedure initiated in response to adetermination that all activated beams satisfy the respective beamfailure criteria, the communications device 104 performs measurements ofthe signal strength (e.g. reference signal received power, RSRP) of theCSI-RS or SSB associated with one or more beams which are configured butnot activated, such as the fourth beam.

The measurements may be compared against a predetermined threshold, suchas an RSRP threshold. If the communications device 104 determines thatthe measurements associated with the fourth beam exceed thepredetermined threshold, then the communications device 104 transmits abeam failure recovery request message (which is an example of a beamfailure indication) as a random access message using a physical randomaccess channel (PRACH) of the new identified beam.

Communications resources on the PRACH may have been previously indicatedas suitable for non-contention based random access transmissions, inwhich case the beam failure recovery request message may be transmittedin a contention-free manner using those resources; otherwise, the beamfailure recovery request message may be transmitted in a contentionbased manner.

After transmitting the beam failure recovery request message, thecommunications device 104 monitors downlink communications resourcesassociated with the new identified beam. More specifically, thecommunications device 104 may monitor a configured recovery searchspace, which may be a ‘recoverySearchSpace’, having as an identity a‘recovery SearchSpaceId’, for downlink control information (DCI).

If the communications device 104 receives downlink control informationin the configured communications resources, which indicates thatcommunications resources on a shared downlink channel (such as thephysical downlink shared channel, PDSCH) are scheduled to be used forthe transmission by the infrastructure equipment 101 of a response tothe beam failure recovery request message, then the communicationsdevice 104 determines that the beam failure recovery is successful.

In response to receiving the downlink control information, thecommunications device 104 sets the new identified beam as an activatedbeam. The new (activated) beam can be used for subsequent communicationsbetween the infrastructure equipment 101 and the communications device104, including the transmission of control information to indication oneor more beams which are to be activated for the communications device.The communications device 104 may decode and process data transmittedusing the scheduled communications resources on the shared downlinkchannel, for example in a conventional manner

Beam Management Resources

Collectively, communications resources associated with assessment of abeam against its beam failure criteria, beam management and the beamfailure recovery procedure may be referred to as beam managementresources. These may include downlink resources on which CSI referencesignals or SSB are transmitted, uplink PRACH resources, and the recoverysearch space. Where beam management resources are associated with a BWP,all of the beam management resources may exist within the BWP;alternatively some portion of the beam management resources, such asdownlink SSB communications resources, which are associated with a BWPmay comprise communications resources which are not within thecommunications resources of the respective BWP.

Not all BWPs may be configured with beam management resources. In theevent that beam failure of all activated beams on a given activated BWPis detected and there are no (or insufficient) beam management resourceson that BWP for carrying out the beam failure recovery procedure, thenthe communications device 104 may be unable to carry out the beamfailure recovery procedure until it moves and/or a BWP is activatedwhich does have the necessary beam management resources. Alternatively,the criteria for radio link failure may be determined to be satisfied.

Radio Link Failure

A radio link quality associated with a serving cell (such as the cell103) may be assessed periodically, such as once in each predefined timeduration. The cell's radio link quality may be determined based onmeasurements of signals transmitted on resources associated with theactivated BWP. Predetermined thresholds are used, together with theassess radio link quality, to determine whether a cell which iscurrently in-sync should be declared to higher layers as beingout-of-sync, or vice versa.

Beam Management and Beam Failure with Multiple Activated BWPs

According to some embodiments of the present technique, a single set ofbeam management resources and common beam failure criteria, comprising abeam failure threshold, are used in respect of all beams and all BWPs.

In such embodiments, a same set of beams may be used for each activatedBWP for a given communications device. For example, in contrast to thescenario illustrated in FIG. 5A, in some embodiments, the first to thirdbeams 150, 152, 154 may be activated in respect of each of a pluralityof activated BWPs, such as the first and third BWPs 401 a, 401 c.

Alternatively, the same set of beams are used for channels of the sametype of each activated BWP; for example, a set of PDCCH beams may beused for any PDCCH transmissions, regardless of the BWP on which theyoccur; similarly, all PDSCH transmissions, on all activated BWPs, usethe same set of beams, although this set may differ from the PDCCHbeams.

Beam management resources may be configured on only one of the activatedBWPs, even if two or more BWPs are activated. A single beam failurethreshold, applicable to all activated beams and all activated BWPs maybe pre-determined, e.g. signalled to the communications device 104 bythe infrastructure equipment 101.

FIG. 6 illustrates first to third BWPs 401 a-c configured as describedabove in respect of FIG. 3 ; however, in the embodiment illustrated inFIG. 6 , the third BWP 401 c is designated as a primary BWP and, assuch, remains activated, irrespective of whether one or more of theother (secondary) BWPs 401 a, 401 b are activated.

Where one of the configured BWPs is designated as a primary BWP as inthe example illustrated in FIG. 6 , the beam management resources may beconfigured only on the primary BWP (that is, on the third BWP 401 c ofFIG. 6 ).

If there is no designated primary BWP, and one of the configured BWPs isdesignated as a default BWP then, according to embodiments of thepresent technique, when the default BWP is activated, the beammanagement resources are configured on the default BWP. In addition,beam management resources may be configured on a further non-default BWPin accordance with a predetermined prioritisation scheme, for use in thecase that the default BWP is not activated.

Thus, where a configured BWP is designated as the default BWP and thedefault BWP is not activated, or where no configured BWP is designatedas the default BWP, or in any case, then beam management resources maybe configured on an activated BWP which is not designated as the defaultBWP.

The communications device may determine which one of the activated BWPsis configured with beam management resources in accordance with thepredetermined prioritisation scheme. The activated BWP having theconfigured beam management resources may be determined, in accordancewith the predetermined prioritisation scheme, based on one or morecharacteristics of the BWP (e.g. index number, bandwidth, sub-carrierspacing, and a network-assigned priority). Network-assigned prioritiesmay be assigned explicitly or implicitly to each activated BWP, andpreferably additionally to each configured BWP.

For example, in accordance with the predetermined prioritisation scheme,the beam management resources may be configured on the activated BWPhaving the highest sub-carrier spacing and, where there are two or morehaving the same (highest) sub-carrier spacing, the BWP of those two ormore which has the highest index number.

In another example, in accordance with the predetermined prioritisationscheme, the BWP which is configured with the beam management resourcesmay be the activated BWP having the highest network-assigned priority.

A process which may be implemented in the communications device 104 fordetermining on which BWP beam management resources are configured isshown in FIG. 7 .

The process of FIG. 7 starts at step 530 in which the communicationsdevice 104 determines whether one of the configured BWPs is designatedas the primary BWP. If one is, then control passes to step 540, in whichthe communications device 104 determines that the beam managementresources are configured on the BWP which is designated as the primaryBWP.

If, at step 530, the communications device 104 determines that noconfigured BWP is designated as the primary BWP, then control passes tostep 550.

At step 550, the communications device 104 determines whether one of theconfigured BWPs is designated as a default BWP. If one is, then controlpasses to step 560 in which the communications device 104 determineswhether the default BWP is activated. If it is, then control passes tostep 570 in which the communications device 104 determines that the beammanagement resources are configured on the BWP which is designated asthe default BWP.

If at step 550 it is determined that no configured BWP is designated asa default BWP, or it is determined at step 560 that the default BWP isnot activated, then control passes to step 580, in which thecommunications device 104 determines the BWP on which beam managementresources are configured in accordance with the predeterminedprioritisation scheme.

One or more of the steps of the process of FIG. 7 may be omitted, andthe order of the steps may be altered. For example, in some embodiments,there may be no possibility to designate a BWP as a primary BWP, inwhich case steps 530 and 540 may be omitted, and the process may startat step 550.

In some embodiments, measurements of signals transmitted using theactivated beams are measured on communications resources of the BWP onwhich the beam management resources are configured.

In some embodiments, a single beam failure threshold against which theresults of the measurements are compared may applicable regardless ofthe BWP on which the beam management resources are configured.

In some embodiments, the beam failure threshold may depend on the BWP onwhich the beam management resources are configured; for example, a beamfailure threshold may be configured for each configured BWP, and theapplicable beam failure threshold (i.e. the one against which themeasurements are compared) may be the one associated with the BWP onwhich the beam management resources are configured.

In some embodiments, beam management resources may be configured onmultiple configured BWPs.

In some embodiments, the process of FIG. 7 may be modified to identifyin addition, or alternatively, which beam management resources should beused and/or which beam failure threshold to apply. Specifically, theprocess of FIG. 7 may be modified to determine a BWP which hasassociated beam management resources to be used and/or the beam failurethreshold to be used.

The process of FIG. 7 may be used to determine on which BWP beammanagement resources in response to determining that one or more beamshave been determined as satisfying the beam failure criteria. The beamfailure indication 160 may be transmitted on beam management resourcesof the BWP which is selected in accordance with the process of FIG. 7 .

Where the process of FIG. 7 is initiated in response to determining thatall activated beams satisfy the beam failure criteria and that beamfailure recovery is required, the beam failure recovery may be triggeredusing the communications resources of the determined BWP.

In some embodiments, the infrastructure equipment configures beammanagement resources on a single (activated) BWP. The identity of thisBWP is indicated to the communications device 104, either in advance orwhen the default BWP is deactivated. The indication may be in downlinkcontrol information (DCI) transmitted on a physical downlink controlchannel (PDCCH) or in a layer 2 (L2) signalling message e.g. a radioresource control configuration message (such as an RRC Reconfigurationmessage), or medium access control (MAC) control element.

In embodiments where a single set of beam management resources are used,beam management occurs using the single applicable set of beammanagement resources, independent of the number of activated BWPs. Assuch, the BWP associated with the communications resources on whichmeasurements are made for the purposes of evaluating the beam failurecriteria, and the BWP on which a resulting indication may be transmittedare the same BWP.

In other words, the communications device 104 may perform measurementsof signals transmitted on one or more beams, using communicationsresources associated with the BWP in which the beam management resourcesare determined to be located. Accordingly, the communications device 104may transmit measurement results to the infrastructure equipment usingcommunications resources of the same BWP, which may in response modifythe set of beams (and/or characteristics of the beams) to be used forall activated BWPs for the communications device 104.

Similarly, a beam failure recovery procedure (comprising a transmissionon a PRACH using a non-activated beam associated with a BWP) istriggered when the characteristics of downlink reference signalsreceived on all beams, on the beam management resources associated withthe BWP, fall below the beam failure threshold.

According to some embodiments of the present technique, beam managementresources are configured for each activated BWP. In such embodiments,the set of beams used for each BWP need not be the same. In someembodiments, beam failure criteria may be configured for each BWP andneed not be the same for all BWPs. Preferably, beam failure criteria areconfigured for each BWP in accordance with requirements associated withservices for which the respective BWP may be used.

Beam management (as described above) may thus be performed independentlyin respect of each activated BWP. For example, when a beam of aparticular BWP satisfies the beam failure criteria applicable to thatBWP, beam management resources of that BWP may be used for beammanagement purposes, so that the set of activated beams (orcharacteristics of one or more beams in the set of activated beams) forthat BWP can be adjusted accordingly.

Conventionally, as described above, if all beams for a BWP satisfy thebeam failure criteria, then it is necessary to initiate a beam failurerecovery procedure on that BWP. However, in some embodiments, inresponse to a determination of beam failure with respect to one BWP,then beam management procedures using a different activated BWP may beused to modify the set of activated beams of the BWP on which beamfailure has been detected. Specifically, if one or more beams of thedifferent activated BWP do not satisfy the applicable beam failurecriteria, then the one or more beams may be used for beam managementprocedures in respect of the BWP suffering beam failure. In someembodiments, beam management procedures may be adapted such that anindication of beam failure, such as a beam failure indication,transmitted using a first BWP indicates an identity of a second BWP,where all activated beams of the second BWP satisfy the beam failurecriteria. The beam failure indication may be transmitted using layer 1(L1) or layer 2 (L2) signalling.

Similarly, in some embodiments, beam management procedures may beadapted such that an indication, such as a beam modification message,which notifies the communications device 104 of modified, newlyactivated, and/or newly deactivated beams may comprise an indication ofthe BWP(s) to which the contents of the beam modification messagerelate. The beam modification message may be transmitted using layer 1(L1) or layer 2 (L2) signalling

If beam failure of all activated beams on all activated BWPs has beendetected (i.e. all activated beams on all activated BWPs satisfy therespective beam failure criteria), then a single beam failure recoveryprocedure may be initiated using one of the BWPs.

The selection of the BWP on which to activate the beam failure recoveryprocedure in such circumstances may be selected in a manner similar tothe process illustrated in FIG. 7 and described above. In other words,the beam failure recovery procedure may be carried out using a primaryBWP if one is designated as such; otherwise, the default BWP is used ifit is configured and activated. If no primary BWP is designated and nodefault BWP is activated, then the selection may be in accordance with apriority scheme e.g. in which the BWP having the highest sub-carrierspacing is selected.

In some embodiments, where the process of FIG. 7 is used to determinethe BWP on which to perform beam failure recovery, the process may bemodified as follows. If at step 530 it is determined that a primary BWPis designated, then a determination is made as to whether beam failureof all activated beams on the primary BWP has occurred. If not, thecontrol continues to step 540 as indicated in FIG. 7 . Otherwise, thenit may not be possible to perform beam failure recovery using theprimary BWP and control may pass to either step 550 (determination ofwhether default BWP is configured) or directly to step 580 (select BWPbased on prioritisation scheme).

Additionally or alternatively, in some embodiments, step 580 may becarried out, instead of step 570, in response to a determination (whichmay be carried out prior to step 570) that beam failure of all activatedbeams on the default BWP has occurred.

FIG. 8 illustrates a process which may be carried out by thecommunications device 104 in response to determining that an activatedbeam used for an activated BWP satisfies the beam failure criteria forthe activated BWP. For example, as described above, this may occur if asignal strength of quality of signals of the activated beam falls belowa beam failure threshold.

The process starts at step 610 in which the communications device 104determines that the signals received on an activated beam used for anactivated BWP (for example, the first BWP 401 a) meet beam failurecriteria applicable to beams on the first BWP 401 a.

The process continues at step 620, in which the communications device104 determines whether all activated beams on the first BWP 401 a meetthe beam failure criteria applicable to the first BWP 401 a.

Otherwise (for example because signals of one or more activated beamsused for the first BWP 401 a are measured at or above the beam failurethreshold), control passes to step 630. If signals of all activatedbeams used for the first BWP 401 a meet the beam failure criteriacontrol passes to step 640.

In step 630, the communications device 104 initiates beam managementprocedures using the first BWP 401 a. For example, the communicationsdevice 104 may transmit using a control channel associated with thefirst BWP 401 a a control message which may indicate measurement resultsof signals of one or more activated beams and configured (but notactivated) beams for the first BWP 401 a.

In response to receiving the control message, the infrastructureequipment 101 may adapt characteristics of one or more of the beamsconfigured for the first BWP 401 a, and may transmit an indication tothe communications device 104 to modify the set of activated beams andconfigured beams for the first BWP 401 a.

In step 640, the communications device 104 determines whether, for eachactivated BWP, all activated beams for that BWP have met the applicablebeam failure criteria for that BWP. If not, then control passes to step650; if they have (in other words, all activated beams on all activatedBWPs meet the beam failure criteria applicable to the respectiveactivated BWP), then control passes to step 660.

In step 650, the communications device 104 selects, from the activatedBWPs, a BWP having at least one activated beam which does not meet theapplicable beam failure criteria. The selected BWP (for example, thesecond BWP 401 b) may be selected based on a prioritisation scheme, orpre-configured. Control then passes to step 670.

In step 670, using beams of the second BWP 401 b selected at step 650,the communications device 104 initiates a beam management procedure inrespect of the first BWP 401 a. As a result of the beam managementprocedure, the infrastructure equipment modifies the set of activatedand/or configured beams for the first BWP 401 a, and transmits usingcommunications resources of the second BWP 401 b an indication of themodified beams to be used (i.e. configured and/or activated) to thecommunications device 104.

In step 660, the communications device 104 selects, from the activatedBWPs, a BWP (for example, the third BWP 401 c) on which to initiate abeam failure recovery procedure. In some embodiments, the selection ofthe BWP in this step may be according to the same prioritization schemeor configuration as for selecting a BWP in step 650 for carrying out thebeam management procedure of step 670. Control passes from step 660 tostep 680.

At step 680 the communications device 104 initiates a beam failurerecovery procedure, in respect of all activated BWPs. This may comprisethe transmission of a beam failure recovery request message on a PRACHassociated with the selected BWP 401 c.

As part of the beam failure recovery procedure of step 680, thecommunications device 104 may carry out measurements of signalstransmitted using CSI-RS or SSB associated with any beams which areconfigured but not activated, which are associated with any of theactivated BWPs. The results of these measurements may be indicated in atransmission to the infrastructure equipment.

As such, in some embodiments, in response to determining that beamfailure criteria have been satisfied in respect of one or more beamsassociated with a particular BWP, the communications device 104 maytransmit an indication in response, to the infrastructure equipment 101using communications resources associated with a different BWP.

According to some embodiments of the present technique, where multipleBWPs are activated, assessment of a cell's radio link quality may bedetermined based measurements of signals transmitted on resourcesassociated with a primary BWP (if designated), a default BWP (ifconfigured and activated), or in accordance with a predeterminedprioritisation scheme. For example, the BWP on which resources are to bemeasured for the purposes of radio link quality assessment may bedetermined in a similar manner to the process for determining the BWP onwhich beam management resources are to be used, shown in FIG. 7 anddescribed above. For example, when only one activated BWP is configuredwith beam management resources, radio link quality measurements may bemade only of signals transmitted using resources on the BWP having theconfigured beam management resources.

In some embodiments, for example where beam management resources may beconfigured on multiple BWPs, radio link quality measurements may be madeof signals transmitted using resources on one or more BWPs havingconfigured beam management resources.

In accordance with embodiments of the present technique, there may beavoided the need to provide or configure resources for beam failurerecovery on each activated BWP. In some embodiments, there may be areduced likelihood of beam failure recovery procedure.

By providing beam failure criteria applicable to each BWP, criteria canbe set appropriately for each BWP according to, for example, theservice(s) provided on the respective BWP (e.g. different thresholds forbeam failure detection and identification of a new beam).

Thus there has been described a communications device for use in awireless communications network, the wireless communications networkcomprising an infrastructure equipment providing a wireless accessinterface within a system bandwidth, the system bandwidth comprising aplurality of bandwidth parts, the communications device comprising atransmitter configured to transmit signals using a plurality ofactivated bandwidth parts, a receiver configured to receive signalsusing the plurality of activated bandwidth parts, the received signalsbeing signals transmitted using a plurality of activated beams, and acontroller configured to control the transmitter and the receiver sothat the communications device is operable: to determine that anactivated beam associated with a first bandwidth part satisfies beamfailure criteria; to select from the plurality of activated bandwidthparts a second bandwidth part; and to transmit using communicationsresources associated with the selected second bandwidth part a beamfailure indication indicating that the activated beam associated withthe first bandwidth part satisfies the beam failure criteria.

It will be appreciated that while the present disclosure has in somerespects focused on implementations in an LTE-based and/or 5G networkfor the sake of providing specific examples, the same principles can beapplied to other wireless telecommunications systems. Thus, even thoughthe terminology used herein is generally the same or similar to that ofthe LTE and 5G standards, the teachings are not limited to the presentversions of LTE and 5G and could apply equally to any appropriatearrangement not based on LTE or 5G and/or compliant with any otherfuture version of an LTE, 5G or other standard.

It may be noted various example approaches discussed herein may rely oninformation which is predetermined/predefined in the sense of beingknown by both the base station and the communications device. It will beappreciated such predetermined/predefined information may in general beestablished, for example, by definition in an operating standard for thewireless telecommunication system, or in previously exchanged signallingbetween the base station and communications devices, for example insystem information signalling, or in association with radio resourcecontrol setup signalling, or in information stored in a SIM application.That is to say, the specific manner in which the relevant predefinedinformation is established and shared between the various elements ofthe wireless telecommunications system is not of primary significance tothe principles of operation described herein. It may further be notedvarious example approaches discussed herein rely on information which isexchanged/communicated between various elements of the wirelesstelecommunications system and it will be appreciated such communicationsmay in general be made in accordance with conventional techniques, forexample in terms of specific signalling protocols and the type ofcommunication channel used, unless the context demands otherwise. Thatis to say, the specific manner in which the relevant information isexchanged between the various elements of the wirelesstelecommunications system is not of primary significance to theprinciples of operation described herein.

It will be appreciated that the principles described herein are notapplicable only to certain types of communications device, but can beapplied more generally in respect of any types of communications device,for example the approaches are not limited to machine type communicationdevices/IoT devices or other narrowband communications devices, but canbe applied more generally, for example in respect of any typecommunications device operating with a wireless link to thecommunication network.

It will further be appreciated that the principles described herein arenot applicable only to LTE-based wireless telecommunications systems,but are applicable for any type of wireless telecommunications systemthat supports a random access procedure comprising an exchange of randomaccess procedure messages between a communications device and a basestation.

Further particular and preferred aspects of the present invention areset out in the accompanying independent and dependent claims. It will beappreciated that features of the dependent claims may be combined withfeatures of the independent claims in combinations other than thoseexplicitly set out in the claims.

Thus, the foregoing discussion discloses and describes merely exemplaryembodiments of the present invention. As will be understood by thoseskilled in the art, the present invention may be embodied in otherspecific forms without departing from the spirit or essentialcharacteristics thereof. Accordingly, the disclosure of the presentinvention is intended to be illustrative, but not limiting of the scopeof the invention, as well as other claims. The disclosure, including anyreadily discernible variants of the teachings herein, define, in part,the scope of the foregoing claim terminology such that no inventivesubject matter is dedicated to the public.

Respective features of the present disclosure are defined by thefollowing numbered paragraphs:

Paragraph 1. A communications device for use in a wirelesscommunications network, the wireless communications network comprisingan infrastructure equipment providing a wireless access interface withina system bandwidth, the system bandwidth comprising a plurality ofbandwidth parts, the communications device comprising a transmitterconfigured to transmit signals using a plurality of activated bandwidthparts, a receiver configured to receive signals using the plurality ofactivated bandwidth parts, the received signals being signalstransmitted using a plurality of activated beams, and a controllerconfigured to control the transmitter and the receiver so that thecommunications device is operable: to determine that an activated beamassociated with a first bandwidth part satisfies beam failure criteria;to select from the plurality of activated bandwidth parts a secondbandwidth part; and to transmit using communications resourcesassociated with the selected second bandwidth part a beam failureindication indicating that the activated beam associated with the firstbandwidth part satisfies the beam failure criteria.

Paragraph 2. A communications device according to paragraph 1, whereinthe beam failure criteria comprises a threshold applicable to a measuredcharacteristic of received signals, and the communications device isoperable to measure the characteristic of signals received oncommunications resources associated with the first bandwidth part.

Paragraph 3. A communications device according to paragraph 1 orparagraph 2, wherein a one of the plurality of activated bandwidth partsis designated as a primary bandwidth part which is activated while atleast one other bandwidth part is activated and the first bandwidth partis the bandwidth part designated as the primary bandwidth part.

Paragraph 4. A communications device according to paragraph 1 orparagraph 2, wherein each of the plurality of activated bandwidth partsis either a default bandwidth part having a highest activation priorityor a non-default bandwidth part having an activation priority which islower than the activation priority of a default bandwidth part, and thefirst bandwidth part is the default bandwidth part.

Paragraph 5. A communications device according to paragraph 1 orparagraph 2, wherein the first bandwidth part is selected from theplurality of activated bandwidth parts in accordance with apredetermined prioritisation scheme.

Paragraph 6. A communications device according to any of paragraphs 1 to5, wherein the controller is configured to control the receiver so thatthe communications device is operable to receive an indicationindicating that beam failure indications are to be transmitted usingcommunications resources associated with the selected second bandwidthpart.

Paragraph 7. A communications device according to any of paragraphs 1 to6, wherein the first bandwidth part is associated with a subset of theplurality of activated beams, the controller is configured to determinethat each of the subset of activated beams associated with the firstbandwidth part satisfies the beam failure criteria, and the beam failureindication indicates that all activated beams associated with the firstbandwidth part satisfy the beam failure criteria.

Paragraph 8. A communications device according to paragraph 7, whereinthe second selected bandwidth part is selected from the plurality ofactivated bandwidth parts in accordance with a predeterminedprioritisation scheme.

Paragraph 9. A communications device according to any of paragraphs 1 to8, wherein the beam failure indication comprises an indication of anidentity of the first bandwidth part.

Paragraph 10. A communications device according to any of paragraphs 1to 9, wherein each of the plurality of activated bandwidth part isassociated with a subset of the plurality of activated beams, thecontroller is configured to determine that all beams within each of thesubsets of activated beams associated with each of the plurality ofactivated bandwidth parts satisfy the beam failure criteria, and thebeam failure indication indicates that all activated beams associatedwith the plurality of activated bandwidth parts satisfy the beam failurecriteria.

Paragraph 11. A communications device according to any of paragraphs 1to 10, wherein the beam failure criteria associated with each of theplurality of activated bandwidth parts are the same.

Paragraph 12. A communications device according to any of paragraphs 1to 10, wherein the beam failure criteria associated with the firstbandwidth part differs from beam failure criteria associated with theselected second bandwidth part.

Paragraph 13. A communications device according to any of paragraphs 1to 11, wherein the first bandwidth part and the second bandwidth partare the same bandwidth part.

Paragraph 14. A communications device according to any of paragraphs 1to 12, wherein the first bandwidth part and the second bandwidth partare different bandwidth parts.

Paragraph 15. Infrastructure equipment for use in a wirelesscommunications network, the infrastructure equipment providing awireless access interface within a system bandwidth, the systembandwidth comprising a plurality of bandwidth parts, the infrastructureequipment comprising a transmitter configured to transmit signals to acommunications device using a plurality of activated bandwidth parts andusing a plurality of activated beams, a receiver configured to receivesignals from the communications device using the plurality of activatedbandwidth parts, and a controller, configured to control the transmitterand the receiver so that the infrastructure equipment is operable: toreceive a beam failure indication indicating that an activated beamassociated with a first activated bandwidth part satisfies beam failurecriteria, the beam failure indication transmitted using communicationsresources associated with a second activated bandwidth part.

Paragraph 16. Infrastructure equipment according to paragraph 15,wherein the beam failure criteria comprises a threshold applicable to ameasured characteristic of received signals.

Paragraph 17. Infrastructure equipment according to paragraph 15 orparagraph 16, wherein a one of the plurality of activated bandwidthparts is designated as a primary bandwidth part which is activated whileat least one other bandwidth part is activated and the first bandwidthpart is the bandwidth part designated as the primary bandwidth part.

Paragraph 18. Infrastructure equipment according to paragraph 15 orparagraph 16, wherein each of the plurality of activated bandwidth partsis either a default bandwidth part having a highest activation priorityor a non-default bandwidth part having an activation priority which islower than the activation priority of a default bandwidth part, and thefirst bandwidth part is the default bandwidth part.

Paragraph 19. Infrastructure equipment according to paragraph 15 orparagraph 16, wherein the first bandwidth part is selected from theplurality of activated bandwidth parts in accordance with apredetermined prioritisation scheme.

Paragraph 20. Infrastructure equipment according to any of paragraphs 15to 19, wherein the controller is configured to control the transmitterso that the infrastructure equipment is operable to transmit anindication indicating that beam failure indications are to betransmitted using communications resources associated with the selectedsecond bandwidth part.

Paragraph 21. Infrastructure equipment according to any of paragraphs 15to 20, wherein the first bandwidth part is associated with a subset ofthe plurality of activated beams, and the beam failure indicationindicates that all activated beams associated with the first bandwidthpart satisfy the beam failure criteria.

Paragraph 22. Infrastructure equipment according to paragraph 21,wherein the second bandwidth part is selected from the plurality ofactivated bandwidth parts in accordance with a predeterminedprioritisation scheme.

Paragraph 23. Infrastructure equipment according to any of paragraphs 15to 22, wherein the beam failure indication comprises an indication of anidentity of the first bandwidth part.

Paragraph 24. Infrastructure equipment according to any of paragraphs 15to 23, wherein each of the plurality of activated bandwidth part isassociated with a subset of the plurality of activated beams, and thebeam failure indication indicates that all activated beams associatedwith the plurality of activated bandwidth parts satisfy the beam failurecriteria.

Paragraph 25. Infrastructure equipment according to any of paragraphs 15to 24, wherein the beam failure criteria associated with each of theplurality of activated bandwidth parts are the same.

Paragraph 26. Infrastructure equipment according to any of paragraphs 15to 24, wherein the beam failure criteria associated with the firstbandwidth part differs from beam failure criteria associated with theselected second bandwidth part.

Paragraph 27. Infrastructure equipment according to any of paragraphs 15to 25, wherein the first bandwidth part and the second bandwidth partare the same bandwidth part.

Paragraph 28. Infrastructure equipment according to any of paragraphs 15to 26, wherein the first bandwidth part and the second bandwidth partare different bandwidth parts.

Paragraph 29. Circuitry for an infrastructure equipment for use in awireless communications network, the infrastructure equipment providinga wireless access interface within a system bandwidth, the systembandwidth comprising a plurality of bandwidth parts, the circuitrycomprising transmitter circuitry configured to transmit signals to acommunications device using a plurality of activated bandwidth parts andusing a plurality of activated beams, receiver circuitry configured toreceive signals from the communications device using the plurality ofactivated bandwidth parts, controller circuitry, configured to controlthe transmitter circuitry and the receiver circuitry so that theinfrastructure equipment is operable: to receive a beam failureindication indicating that an activated beam associated with a firstactivated bandwidth part satisfies beam failure criteria, the beamfailure indication transmitted using communications resources associatedwith a second activated bandwidth part.

Paragraph 30. A method or infrastructure equipment for use in a wirelesscommunications network, the infrastructure equipment providing awireless access interface within a system bandwidth, the systembandwidth comprising a plurality of bandwidth parts, the methodcomprising transmitting signals to a communications device using aplurality of activated bandwidth parts and using a plurality ofactivated beams, receiving signals from the communications device usingthe plurality of activated bandwidth parts, and receiving a beam failureindication indicating that an activated beam associated with a firstactivated bandwidth part satisfies beam failure criteria, the beamfailure indication transmitted using communications resources associatedwith a second activated bandwidth part.

Paragraph 31. Circuitry for a communications device for use in awireless communications network, the wireless communications networkcomprising an infrastructure equipment providing a wireless accessinterface within a system bandwidth, the system bandwidth comprising aplurality of bandwidth parts, the circuitry comprising transmittercircuitry configured to transmit signals using a plurality of activatedbandwidth parts, receiver circuitry configured to receive signals usingthe plurality of activated bandwidth parts, the received signals beingsignals transmitted using a plurality of activated beams, and controllercircuitry configured to control the transmitter circuitry and thereceiver circuitry so that the communications device is operable: todetermine that an activated beam associated with a first bandwidth partsatisfies beam failure criteria; to select from the plurality ofactivated bandwidth parts a second bandwidth part; and to transmit usingcommunications resources associated with the selected second bandwidthpart a beam failure indication indicating that the activated beamassociated with the first bandwidth part satisfies the beam failurecriteria.

Paragraph 32. A method for a communications device for use in a wirelesscommunications network, the wireless communications network comprisingan infrastructure equipment providing a wireless access interface withina system bandwidth, the system bandwidth comprising a plurality ofbandwidth parts, the method comprising transmitting signals using aplurality of activated bandwidth parts, receiving signals using theplurality of activated bandwidth parts, the received signals beingsignals transmitted using a plurality of activated beams, determiningthat an activated beam associated with a first bandwidth part satisfiesbeam failure criteria, selecting from the plurality of activatedbandwidth parts a second bandwidth part, and transmitting usingcommunications resources associated with the selected second bandwidthpart a beam failure indication indicating that the activated beamassociated with the first bandwidth part satisfies the beam failurecriteria.

Further particular and preferred aspects of the present invention areset out in the accompanying independent and dependent claims. It will beappreciated that features of the dependent claims may be combined withfeatures of the independent claims in combinations other than thoseexplicitly set out in the claims.

REFERENCES

-   [1] 3GPP TS 38.300 v. 15.2.0 “NR; NR and NG-RAN Overall Description;    Stage 2(Release 15)”, June 2018-   [2] Holma H. and Toskala A, “LTE for UMTS OFDMA and SC-FDMA based    radio access”, John Wiley and Sons, 2009-   [3] TR 38.913, “Study on Scenarios and Requirements for Next    Generation Access Technologies (Release 14)”.

What is claimed is:
 1. A communications device for use in a wirelesscommunications network, the wireless communications network comprisingan infrastructure equipment providing a wireless access interface withina system bandwidth, the system bandwidth comprising a plurality ofbandwidth parts, the communications device comprising a transmitterconfigured to transmit signals using a plurality of activated bandwidthparts, a receiver configured to receive signals using the plurality ofactivated bandwidth parts, the received signals being signalstransmitted using a plurality of activated beams, and a controllerconfigured to control the transmitter and the receiver so that thecommunications device is operable: to determine that an activated beamassociated with a first bandwidth part satisfies beam failure criteria;to select from the plurality of activated bandwidth parts a secondbandwidth part; and to transmit using communications resourcesassociated with the selected second bandwidth part a beam failureindication indicating that the activated beam associated with the firstbandwidth part satisfies the beam failure criteria.